The PLG or poly(lactide-co-glycolide) family of polymers has traditionally been the polymer of choice for drug delivery systems. However, PLG can in some instances generate a pH drop within the polymer matrix, which can be deleterious to the incorporated agent, particularly when the agent is a labile agent such as a protein, polypeptide or oligonucleotide. In addition, the hydrophobic nature of PLG can result in problems with release of the incorporated agent due to adsorption of the agent onto the polymer surface, denaturation of the agent and aggregation of the agent. As such, new polymer compositions which can reduce the problems often encountered during processing of and release in vivo from polymeric sustained release compositions are needed.